This invention relates to a positioner for moving an article along three mutually perpendicular axes and, in particular, to a positioner wherein the controls for each axis are parallel and extend from the same side of the positioner.
Visual inspection of work in progress is used in many industries as part of a quality control process. In the semiconductor industry, for example, integrated circuits are inspected several times during manufacture to assure the accurate completion of each process step, e.g. wire bonding. Each inspection station includes a microscope positioned above a stage for receiving a workpiece and typically includes a positioner for moving the microscope relative to the stage along three axes.
Positioners having three axes of movement are well known in the art and are typified by the positioner disclosed in U.S. Pat. No. 3,046,006 (Kulicke, Jr.) in which fitted plates are moved relative to one another by three threaded adjustments. The plates move along three mutually perpendicular axes and the control knobs for each adjustment extend in three different directions from the positioner. This arrangement of the control knobs is not particularly convenient since one tends to grope for the correct knob while looking through the microscope. Further, the positioner is not as easy to use for a left-handed person as for a right-handed person.
A positioner having all control knobs on one side of the positioner is known in the art. U.S. Pat. No. 4,193,317 (Oono et al.) discloses a positioner in which the knobs for X-axis and Y-axis adjustments are attached to feedscrews engaging female threads attached to a stage. A knob for adjustment along the Z-axis is attached to a feedscrew engaging a cam for raising or lowering the stage. The knobs do not move the stage the same amount for a given amount of rotation of each knob and the range of motion along the Z-axis is much less than the range of motion along the X-axis and the Y-axis. The feedscrews are not parallel and the knobs are connected to the feedscrews by flexible couplings for redirecting the rotational motion of the knobs. Because the motion of the knobs is redirected within the positioner, only a single set of control knobs can be provided. Although the positioner disclosed in the Oono et al. patent appears suitable for its intended purpose, the positioner is not very rugged.
Since not all inspections use a horizontal stage, it is desirable to have a positioner which has interchangeable axes, i.e. the range and travel of the collar is the same in all axes of movement. With interchangeable axes, for example, one can hold a microscope or other inspection device horizontally rather than vertically and the operation of the positioner will feel the same as when the microscope is vertical.
In view of the foregoing, it is therefore an object of the invention to provide a rugged positioner having motion along three axes controlled by a set of knobs located on a single side of the positioner.
A further object of the invention is to provide a positioner having motion along three mutually perpendicular axes controlled by three parallel shafts.
Another object of the invention is to provide a positioner having dual controls on opposite sides of the positioner.
A further object of the invention is to provide a positioner having motion along three, interchangeable, mutually perpendicular axes.
Another object of the invention is to provide a positioner having motion along three mutually perpendicular axes controlled by three knobs all having the same travel, i.e. wherein rotating each knob causes the same amount of movement per turn of the knob.
A further object of the invention is to provide a positioner having the same ranges of motion in three mutually perpendicular axes.
Another object of the invention is to provide a positioner having motion along three mutually perpendicular axes wherein the motion along each axis can be locked.